Intravascular imaging is often used to identify diagnostically significant characteristics of a vessel. For example, an intravascular imaging system may be used by a healthcare professional to help identify and locate blockages or lesions in a vessel. Common intravascular imaging systems include intravascular ultrasound (IVUS) systems as well as light-based imaging systems, such as infrared spectroscopy or optical coherence tomography (OCT) systems.
IVUS systems include one or more ultrasound transducers emitting ultrasound energy based on received electrical signals and sending return electrical signals based on ultrasound energy reflected by various intravascular structures. In some instances, a console with a high-resolution display is able to display IVUS images in real-time. In this way, IVUS can be used to provide in-vivo visualization of the vascular structures and lumens, including the coronary artery lumen, coronary artery wall morphology, and devices, such as stents, at or near the surface of the coronary artery wall. IVUS imaging may be used to visualize diseased vessels, including coronary artery disease. In some instances, the ultrasound transducer(s) can operate at a relatively high frequency (e.g., 10 MHz-60 MHz, in some preferred embodiments, 40 MHz-60 MHz) and can be carried near a distal end of an IVUS catheter. Some IVUS systems involve rotating the IVUS catheter (e.g., mechanically, phased-array, etc.) for 360-degree visualization.
With the advent of higher frequency IVUS imaging systems as well as light-based imaging systems, the precision of the image of the vessel is significantly improved when blood is displaced from the lumen of the vessel. Accordingly, imaging systems may include an injection system configured to deliver a flushing agent into the vessel before the vessel is imaged.